US2619809A - Condenser structure for absorption refrigeration apparatus - Google Patents

Description

1952 s. M. BACKSTROM 2,619,809 CONDENSER STRUCTURE FOR ABSORPTION REFRIGERATION APPARATUS Filed April 6, 1946 2 SHEETSSHEET 1 1 Y IN V EN TOR. WW 3W WM S. M. BACKSTROM Dec. 2, 1952 CONDENSER STRUCTURE FOR ABSORPTION REFRIGERATION APPARATUS 2 Sl-lEETS-SHEET 2 Filed April' 6, 1946 XXX XX'XXXXX A9" I E J INVENTOR. wy/4am Patented Dec. 2, 1952 CONDENSER STRUCTURE FOR ABSORPTION REFRIGERATION APPARATUS Sigurd Mattias Backstriim, Stockholm, Sweden, assignor, by mesne assignments, to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of Sweden Application April 6, 1946, Serial'No. 660,054 In Sweden April 17, 1945 13 Claims. (Cl. 62-1195) This invention relates to air-cooled absorption refrigerating apparatus of the inert gas typ especially apparatus which is adapted for domestic or household use, and has for its object to provide an improvement to simplify the condenser system of such apparatus to obtain greater latitude in mounting and positioning the apparatus in a refrigerator cabinet.

Whereas in compressor-operated refrigerating apparatus a great latitude in the choice of the condenser construction is afforded, certain factors require consideration in the construction of the condenser for an absorption refrigerating apparatus of the inert gas type. In such apparatus relatively small driving forces are developed to efiect liquid circulation and cause inert gas circulation. Even a very small increase in pressure in any part of the apparatusmay Wholly change the different liquid levels therein to such an extent that suitable liquid circulation cannot be effected. Such differences in pressure would easily arise if the resistance to flow of the boiler vapours were increased. Additionally, the presence of the inert gas also presents special problems in the construction of the condenser.

With regard to these factors, one single pipe coil heretofore has generally been used for the condenser of the apparatus and in certain instances a plurality of Such pipe coils connected in series. In such arrangements a venting conduit has been provided for the inert gas which extends from the upper part of the condenser, or the conduit for delivering refrigerant condensate has been employed so that both liquid and gas unobstructedly pass therethrough. Further, it has been proposed to provide condensers of the kind heretofore employed in which the outer surface of the pipe coil alone provides adequate heat dissipating surface to reject and give up heat of condensation to air flowing in-contact therewith. However, in practice it has not been possible, at least in apparatus adapted for household or domestic use, to employ a pipe coil having adequate heat dissipating surface for air cooling and present relatively small resistance to flow of boiler vapours therein. Accordingly, it has heretofore been necessary to arrange cooling fins on the condenser pipes. The long interconnected condenser pipes in the form of coils, in order to operate in a satisfactory way, requires positioning the apparatus in suchmanner that blocking of the condenser by liquid condensate therein is avoided. The longer the condenser pipe and the less the cross-sectional area of the passage of the p pe mp oye rt o e h r b em must-be taken into consideration. In accordance with the invention the foregoing problems areovercome by providing a condenser for absorption refrigerating apparatus of the inert gas type which is constructed in such manner that a plurality of paths of flow are formed for boiler or refrigerant vapours which are connected in pare allel and to which a vent conduit is connected to a region at an upper part of such paths of flow) and supplying the boiler or refrigerant vapours to the condenser so that a column of such vapours is effectively utilized to produce a driving force and promotecirculation of the, vapours in the parallel paths of flow.

The invention, together with the above and other objects and advantages thereof, will be more fully understood upon reference to the fol-'- lowing description and accompanying drawings forming a part of this specification, and of which:

Fig. 1 is a view more or less diagrammatically illustrating a condenser embodying the invention for use in an absorption refrigerating apparatus of the inert gas type;

Fig. 2 diagrammatically illustrates such absorption refrigerating apparatus of the inert gas type? Figs. 3 to 6 illustrate further embodiments'of condensers in accord with the invention which are formed of pipe coils;

Fig. 7 is a perspective view illustrating a still further embodiment of a condenser in accord with the invention which is formed of plate-like members; and

Figs. 8 and 9 are side and top plan views, respectively, of the condenser shown inFig; '7. p

Fig. 1 shows a condenser having conduits for connection in absorption refrigeration apparatus employing inert gas and of a type like that illustrated in Fig. 2. The condenser-comprises two end headers or collector pipes l0- and ,l I. both ends of'the former being closed; Both collector pipes are interconnected with a number of essentially parallel condenser pipes I2, which preferably have a cross-sectional area less than that of the collector pipes. As shown, the pipe system described is step-like in form and is intended to be mounted in the rear compartment of a household refrigerator cabinet and adapted to be cooled by air, the natural draft circulation of which is partly due to heat rejected from the absorber of the refrigerating apparatus also disposedin the flue formed at the rear apparatus compartment. In the following description such a system will be designated a pipe group in a structural'element in condenser systems of large size; Refrigerant vapours expelled from the boiler or vapour expulsion unit of the apparatus, like the boiler 20 in Fig. 1, for example, are supplied to the collector pipe It through a conduit 2 I, which is connected between the two uppermost condenser pipes I2. The condensate formed in the pipe system flows from the collector pipe II, towards which the condenser pipes I2 suitably may incline, through a conduit M which is shaped to form a liquid trap and is connected to the evaporator of the refrigerating apparatus, like the evaporator 21 in Fig. 1, for example. By providing the U-trap in conduit It the: condenser is separated from the gas circulating system. of the apparatus. However, in order to permit inert gas to vent from the condenser system the upper part of the collector pipe I I is connectedtoa vent pipe I5, which communicates with the gas circulating system of the refrigerating apparatus, as at the gas heat exchanger. Such a vent connection from a condenser to the gas circuit is indicated. at I in Fig. 2, for example;

When the apparatus is initially started, the condenser mainly contains inert gas, such as hydrogen gas, which prevents condensation of the penetrating refrigerant vapours. The densityof such vapours, such as ammonia vapour for example, is greater than that of the hydrogen gas; and consequently the greater part of the condenser is filled upwardly from the bottom thereof with ammonia vapour, whilethe hydrogen gas will be gradually forced out from one condenser pipe after another, being finally forced upwardly through the pipe II and the vent pipe l5. However, all of the condenser pipes need not necessarily be filled with ammonia vapour at such a high pressure that condensation will take place- Ifthe cooling of the condenser is good, itis possible that such a large'part of the vapour quantity may condense in the lowest three pipes so'that. the.- partial pressure of the refrigerant vapour in the: upper condenser pipes'will not be sufiiciently high for condensation to take place therein. In such case the. upper condenser pipes still remainfilled with hydrogen gas and act to a certain extent as a pressure equalizing vessel. In the arm A of the end header or collector III, which isfilled with the heavier ammonia vapour, a driving force is produced which causes circulation of. such vapour when some of the condenser. pipesare filled with hydrogen gas'and the vapour in an uncondensed stateor vapour phase tends to seek a path of flow leading to the ventpipe I5; This circulation of vapour grad- 113,113 brings into operation the requisite number of. condenser. pipes for proper functioning of the condenser.

InFig; 2.. is illustrated absorption refrigerating apparatus ofthe inertgas type; Such apparatus,;wh-ich..is well known, includes the boiler 28 in which. refrigerant. vapours are expelled and through a. vapour conduit 2| supplied'to thecondenser system 22. The liquid circulating pump of the. apparatus is denoted by 23, its air-cooled absorber by 24 and its absorber vessel by 25. The absorber and the'absorber vesseloom'municateina well known manner through a liquid heat exchanger 26 with the boiler 20 and the liquid circulating pump 23, respectively; The evaporator of-the apparatus is denoted'by 21 and its gas heat exchangerby' 23. These parts of apparatus form, together-with the absorber and the absorber vessel, the gas circulating system of: the-apparatus, which is built up in a well known manner.

In Fig. 2 the condenser system 22 includes two pipe coils 30 and 3|, disposed in two parallel vertical planes. The upper part of the coil 30 is connected to the vapour conduit 2|, while the upper part-of thecoil 3 isconnected to the pressureequalizing vessel of the apparatus, denoted by 32, for which vessel the coil 3| at the same time serves as a drain conduit for condensate which may be formed therein. The pressure equalizing vessel is connected by the vent conduit I5 to the gas circulating system of the apparatus. The lower ends of both the pipe coils. 3-0. and.3| are. connected to a common conduit 3d,. through which refrigerant condensate is fed to the evaporator 21. The conduit 34 is arranged in. heat exchange relation with the conduitilfi, through which the inert gas flowing to the absorber is conducted from the evaporator 2.3. It is to be understood that the condenser system of Fig. 1 and described above may be connected in absorption refrigeration apparatus of the kindshown inFig.

Figs. 3 and 4 show further embodimentsof the condenser system according to the. invention. The arrangementaccording to Fig. 3 comprises two pipe groups coupledtogether and of thetype shown. in Fig. 1, both pipe groups suitablybeing of the same dimensions and connected by a con-.- duit All. The reference characters correspond to those. of Figs. 1 and 2. The boiler vapours hence flow from the conduit 2| into the first pipe group, which is denoted by 4|, whereby thegas forced through. the. conduit 40 is transferred to. the lowest part of the pipe group 42. and through its left-handend header or collector pipe to thepressure equalizing vessel 32. Both right-hand arms or end headers of the pipe groups are connected. to a conduit 43. through which refrigerant condensate is conducted through the liquid trap- I4 to the evaporator of theapparatus- Fig. 4 shows acondenser system comprising three pipe groups according to: Fig. 1. The vapour conduit. ZI-is connected to theleft end headeror arm of each of the three pipe groups 4|, 42 andM at pointswhich' are: located between the tw uppermost-horizontal pipes of each pipe group. The upper ends of the left-hand end headers or vertical pipes ofthe pipe groups are mutually interconnected by the conduit 45; The inert gasis forced out from one system after the other and is vented through the upper-pipe of the pipe group-1M". to the vent'conduit I5. The difference/in density in the left and right standpipes or-risers of the pipe groups, described in connection. with Fig. 1, will then bring about the successive forcing'out of the inert gas from one group after another."

Figs. 5'and 6 showfurther'embodiments of the condenser system according to the invention and differ from the earlier embodiments essentially in thatthe pipe groups are placed in different horizontal planes parallel to another. The ref erence characters correspond to those of the preceding figures. The connection of the pipe groups is believed to be sufiiciently clear in the drawings. As shown in Fig. 5, the different pipe groups are connected to a common outlet conduit {36' for condensate, which is conducted through it is suitable to arrange the horizontal pipe .distances in such manner that they are disposed groups, respectively, in the manner described above, it is possible, without any danger of liquid blocking, to select pipes of small internal diameter in such number and with such a large external jacket or heat dissipating surface that the condenser will function properly with air-cooling and yet not require additional heat dissipating fins or similar members. In those cases when for some reason or other it is desired to limit the total pipe length of the condenser, heat dissipating fins or the like may, of course, be employed in a Well known manner. It is desirable in such case to arrange the fins so that the upwardly flowing air stream passing from the lower located absorber of the refrigerating apparatus will pass in intimate contact with the fins in the fin packet and will be directed through the central part thereof. This is accomplished by arranging the condenser pipes in the packet so that pipes will be disposed over a greater part of the horizontal cross-section of the air flue.

The invention may be further developed in such manner that the pipegroups are replaced by fiat hollow structures welded from sheet metal members, as diagrammatically shown in Figs. '7,

-8 and 9. Fig. 7 shows a condenser system comprising three similar flat hollow structures 55,

the upper parts of which are connected by conduits 5| and 52. The supply conduit for refrigerant vapours is denoted by 2| and the discharge conduit for refrigerant condensate by hi. In order to couple the hollow structures 58 together it may be suitable to form the structures in the manner shown in Fig. 8. Fig. 9 shows a condenser system built up of members like that shown in Fig. 8. As shown, the hollow structures 50 are formed of pressed plates which preferably are congruent with respect to one another and welded together in pairs along their edges and which in other respects are shaped and joined together in a well known manner in the manufacture of heat-radiators. Due to the high pressure generally prevailing in the apparatus, which pressure may exceed 20 atmospheres, the opposing plates of each hollow structure 53 are united together not only along their edges but also at a. number of welded points 55. At these points the plates before being welded together are impressed in such a way that, when the plates are placed together with the concave sides against each other, the convex surfaces of the impressions will lie in pairs against each other. Thereafter the plates of each hollow structure are united together by electrical resistance welding. In order to facilitate the mounting of the hollow structures 50 the connecting openings are arranged in ears 56, which then, as will be clear from Fig. 9, will be placed close to each other,

thus forming through conduits 5! to which the interconnecting conduits of the apparatus are coupled. Byconnecting the vapour conduit 2l fromtheboiler to the upper ends of the flat hol- .6 low structures 50, as shown in Fig. 'l, a'fiow' within the system will be effected, which causes an equalization of the loading of the condenserdue to the hydrogen gas being gradually forced out through the vent conduit.

In view of the foregoingit willnow be understood that in the different embodiments illustrated and described above refrigerant: vapour is introduced into an end header or a collector of a condenser unit to form a column. of such vapour which is effectively utilized as a driving force to promote circulation of refrigerant vapour in a plurality of horizontally extending passages connected at their ends to the vertically extending end headers. Each end-header independently. of the other end header serves to establish fluid communicationbetween all ofthe horizontally extending passages embodied in each condenser unit or section and connected thereto.

In Figs. 1, 3, 4 and 5 the conduit 2| for conducting refrigerant vapour from the boiler or vapour expulsion unit is connected at a region of the end collector which is located between the highest and next highest horizontally extending pipes or pipe elements'forming the passageways. In the different embodiments the horizontally extending passages or pipes are distributed in a vertical range between a low and higher-level and disposed at three or more different levels. Hence, refrigerant vapour is introduced into a vertically extending passage or end header at a region which is above the connection thereto of at least two or more pipes at different levels and above at least half of the different levels at which the horizontally extending passages or pipe elements are disposed.

The invention is not to be limited to the embodiments shown but may be varied in several ways with in the scope of the basic inventive idea. It is essential for the condenser system to be vented from a region thereof located sufiiciently. high within the system so that no hydrogen gas worth mentioning will collect above such region. Further, the condenser system desirably should be mounted in such manner that, due to, the difference in density of inert gas and refrigerant vapour, an internal circulation will be established and an increasingly greater part of the condenser will be made available to function and liquefy refrigerant vapour by displacing hydrogen gas through the vent conduit.

Reference is made to applicants divisional ap plication Serial No. 210,908, filed February 14, 1951, which claims features of the absorption refrigeration apparatus disclosed in Figs. 7, 8 and 9.

I claim:

1. In air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fluid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising condenser structure including first and second vertically disposed conduits in spaced apart relation, a plurality of horizontally extending pipes arranged at least at three different levels, each of said pipes having one end thereof connected to said first conduit .and the opposite end thereof connected to said second conduit, the cross-sectional areas of said conduits being greater than the crosssectional areas of said pipes and forming vertical end headers, said first conduitconstituting means for establishing fluid communication between all ofsaid pipes which are embodied in said condenser structure and connected thereto, said, second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in said condenser structure and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit to an end header of said condenser structure at a'level which is above the connection thereto of the lowest pipe and below the connection thereto of the highest pipe, conduit means communicating with an end header of said condenser structure for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicating with an upper part of said condenser structure for venting inert gas therefrom to the gas circuit;

2. In air-cooled absorption refrigeration apparatus employing hydrogen as an inert gas and ammonia as a refrigerant, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising condenser structure including first and second vertically disposed conduits in spaced apart relation, a plurality of horizontally extending pipes arranged at least at three different levels, each of said pipes having one end connected to said first conduit and the opposite end connected to said second conduit, the crosssectional areas of said conduits being greater than the cross-sectional areas of said pipes and forming vertical end headers, said first conduit constituting means for establishing fluid communication between all of said pipes which are embodied in said condenser structure and connected thereto, said second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in said condenser structure and connected thereto, conduit means for delivering refrigerant vapor from the vapor expulsion unit to said first conduit at a region between the connections thereto of said pipe at the highest level and the pipe at the next highest level, conduit means communicating with the lower end of said second conduit for conducting liquid refrigerant therefrom to the evaporator structure, all of said pipes being inclined to drain liquid therefrom by gravity to said second conduit, and conduit means communicating with an upper part of said condenser structure for venting inert gas therefrom to the gas circuit.

3. In an air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fluid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising condenser structure including first and second vertically disposed conduits in spaced apart relation, a group of horizontally extending pipes distributed vertically in the space between said conduits, each pipe having one end connected to said first conduit and the opposite end connected to said second conduit, said conduits being of greater diameter than said pipes and forming vertical end headers, each of said conduits constituting independent means for establishing fluid communication between all of said pipes which are embodied in said condenser structure and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit to an end header of said condenser structure at a region which is above the connection thereto of at least two or more pipes atdifferent: levels, conduit means communicating with an end header of said condenser structure for conducting liquid refrigerant therefrom to the evaporator, and conduit means communicating; with an upper part of said condenser structure for venting inert gas therefrom to thegas circuit;

4. In an air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fluid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant. to the evaporator structure, comprising condenser structure including first and second vertically disposed conduits in spaced apart relation, 2. group of horizontally extending pipe elements between said conduits which are disposed at three or more difierent levels, all of said pipe elements at one end of the group being connected to said first conduit and at the opposite end thereof being connected to said second, conduit, each of said first and second conduits forming a vertical end header which constitutes means for establishing fluid communication between all of said pipe elements which are embodied in said condenser structure and connected thereto, conduit means for delivering refrigerant vapor from the vapor expulsion unit to an, end header of said condenser structure at a region which is above at least half of the different levels at which said pipe elements are disposed, conduit means communicating with an end header of said condenser structure for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicatin with an upper part of said condenser structure for venting inert gas therefrom to the gas circuit.

5. In air-cooled absorption refrigeration apparatus containing an inert gas and a refrigerant which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising a condenser unit including structure providing vertically extending passages forming end headers which are in spaced apart relation and also providing a group of horizontally extending passageways which are distributed in a vertical range and positioned at three or more different levels, one of said end headers being connected to one end of said horizontally extending passages and the other end header being connected to the opposite end of such passages, each of said end headers constituting independent means for establishing fluid communication between all of the horizontally extending passageways embodied in said condenser unit and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit to said one end header at a region which is above at least half of the different levels at which said horizontally extending passageways are disposed, conduit means communicating with said other end header for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicating with the upper part of said condenser unit for venting inert gas therefrom to the gas circuit.

6. In air-cooled absorption refrigeration apparatus containing an inert gas and a refrigerant which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unitfor producing-refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising condenser structure including a group of horizontally extending pipe elements distributed in a vertical range disposed between a low level and a higher level and having pipes positioned at three or more difierent levels, first conduit means for connecting all of said pipe elements at one end of said group and establishing fluid communication at such one endof all of said pipe elements which are embodied in said condenser structure, second-conduit means for connecting all of said pipeelements at the opposite end of said group and establishing fluid communication at such opposite end of all of said pipe elements which are embodied in said condenser structure, third conduit-means for delivering refrigerant vapor from the vapor expulsion unit to said first conduit means at a region thereof which is above and below the pipe elements disposed at said low and higher levels, respectively, fourth conduit means communicating with said second conduit means for conducting liquid refrigerant frigerant to the evaporator structure comprising condenser structure including a group of horizontally extending pipe elements distributed at three or more different levels in a Vertical range disposed between a low level and a higher level, first conduit means for connecting all of said pipe elements at one end of the group and establishing fluid communication at such one end of all of said pipe elements which are embodied in said condenser structure, second conduit meansfor connecting all of said pipe elements at the oppqsite end of the group and establishing fluid communication at such opposite end of all of said pipe elements which are embodied in saidcondenser structure, third conduit means for delivering refrigerant vapor from the vapor expulsion unit to said first conduit means at a region which is above at least half of the different levels at which said pipe elements are distributed, fourth conduit means communicating with said second conduit means for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicating with an upper part of said condenser structurefor venting ine t gas therefom .to the gas cicuit.

8. In an air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fluid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising a plurality of condenser sections, each of said sections including first and second vertically disposed conduits in spaced apart -re-' lation and a plurality of horizontally extending pipesarranged at least at three different levels, 'each of said pipes having one end connected' to said'first conduit and the opposite end connected to said second conduit, the crosssectional areas of said conduits being greater 10 than the cross-sectional areas of said pipes and forming end headers, said first conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, said second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit to the end headers of a plurality of said condenser sections at regions which are above the connection of the lowest pipe to each such end header and below the connection of the highest pipe to each such end header, conduit means communicating with an end header of each such condenser section for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means com-,

municating with an upper part of each such condenser section for venting inert gas therefrom to the gas circuit.

9. In an air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fluid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising first and second condenser sections, each of said sections including first and second vertically disposed conduits in spaced apart relation and a plurality of horizontally extending pipes arranged at least at three different levels, each of said pipes having one end connected to said first conduit and the opposite end connected to said second conduit, the cross-sectional areas of said conduits being greater than the cross-sectional areas of said pipes and forming end headers, said first conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, said second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, conduit means for conducting refrigerant'vapor from the vapor expulsion unit to an end header of the first condenser section at -a region which is above the connection of the lowest pipe thereto and below the connection of the highest pipe thereto, conduit means connecting an upper part of said first condenser section and an end header of said second condenser section, conduit means communicating with an end header of each condenser section for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicating with an upper par-t of said second condenser section for venting inert gas therefrom to the gas circuit.

10. In aircooled absorption refrigeration apparatus employing hydrogen as an inert gas and ammonia as a refrigerant, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising a plurality of condenser sections, each of said sections including. first and second vertically disposediconduits in spaced apart relation, a plurality of horizontally extending pipes arranged at least at three. different levels, each of said pipes havingone end connectedto said tional areas of said pipes and forming vertical end headers, said first conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, said second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto,conduit means for conducting refrigerant vapor from the vapor expulsion unit to the first conduits of a plurality of said condenser sections at regions between the connections to each such first conduit of said pipe at thehighest level and the pipe at the next highest level, conduit means communicating with the lower ends of the second conduits of each such condenser section for conducting liquid refrigerant therefrom to the evaporator structure, all of said pipes being inclined downwardly to drain liquid therefrom by gravity to the second conduits of said sections, and conduit means communicating with an upper part of each such condenser section for venting inert gas therefrom to th as circuit.

11. In air-cooled absorption refrigeration apparatus employing hydrogen as an inert gas and ammonia as a refrigerant, a gas circuit including evaporator structure, and a vapor expulsion unit for producing refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising first and second condenser sections, each of said sections including first and second vertically disposed conduits in spaced apart relation, a, plurality of horizontally extending pipes arranged at least at three different levels, each of said pipes having one end.

connected to said first conduit and the opposite end connected to said second conduit, the crosssectional areas of said conduits being greater than the cross-sectional areas of said pipes and forming vertical end headers, said first conduit constituting means for establishing fiuid communication between all of said pipes which are embodied in the condenser section and connected thereto, said second conduit constituting means for establishing fluid communication between all of said pipes which are embodied in the condenser section and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit to the first conduit of said first condenser section at a region between the connections thereto of the pipe at the highest level and the pipe at the next highest level, conduit means connecting the upper end of the second conduit of said first condenser section and the lower end of the first conduit of said second condenser section, conduit means communicating with the lower ends of the second conduits of said'first and second condenser sections for conducting liquid refrigerant therefrom to the evaporator structure, all of said pipes beinginclined downwardly to drain liquid therefrom by V a plurality of condenser sections, each-section including first and second vertically disposed con duits in spaced apart relation, a group of horizontally extending pipes distributed vertically in the space between said conduits, each pipe having one end connected to said first conduit and the opposite end connected to said second conduit, said conduits being of greater diameter than said pipes and forming vertical end headers, each of said conduits constituting inde pendent means for establishing fiuid communication between all of said pipes which are embodied in the condenser section and connected thereto, conduit means for conducting refrigerant vapor from the vapor expulsion unit-to the end headers of a plurality of said condenser sections at regions of each such end header which are above the connection thereto of at least two or more pipes at different levels, conduit means communicating with end headers of each such condenser section for conducting liquid refrigerant therefrom to the evaporator structure, and conduit means communicating with an upper part of each such condenser section for vent ing inert gas therefrom to the gas circuit.

13. In an air-cooled absorption refrigeration apparatus containing an inert gas and refrigerant fiuid which in vapor phase is denser than the gas, a gas circuit including evaporator structure, and a vapor expulsion unit for producing.

refrigerant vapor, means for supplying liquid refrigerant to the evaporator structure comprising first and second condenser sections, each. of said sections including first and second vertically disposed conduits in spaced apart relation, 9.

nected thereto, conduit means for conducting. re-- frigerant vapor from the vapor expulsion unit. to an end header of said first condenser section at a region which is above the connection thereto of at least two'or more pipes atdiiferent levels, conduit meansconnecting the upper part of said first condenser section and an end header of said second condenser section, conduit means communicating with end headers of said first and second condenser sections for conducting liquid refrigerant therefrom to the evaporator structure, and conduit-means communicating with an upper part of said second condenser section for venting inert gas therefrom to the gas circuit.

SIGURD MATTIAS BACKSTRGM.

REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,958,899 MacAdams May 15, 1934 2,243,903 I-Iintze June 3, 1941 2,302,091 Anderson Nov. 17, 1942 2,350,347 Gaugler June 6, 1944 2,422,401 Gaugler June 17, 1947

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